The present invention relates to a switching valve for switching a fluid passage, a fluid compressor with a casing containing the switching valve, and a heat pump type refrigeration cycle including the fluid compressor.
In an air-conditioning apparatus having a heat pump type refrigeration cycle in which a cooling drive mode and a heating drive mode can be easily switched, the switching of the drive mode is effected by changing the direction of passage of a fluid or a refrigerant gas.
In the prior art, the passage of refrigerant gas is changed by means of a four-way valve provided in the refrigeration cycle. The four-way valve comprises one inlet portion provided in the valve casing and three outlet portions linearly arranged on the side opposite to the inlet side. Two of the three outlet portions are always closed by the valve body.
The valve body is driven by an electromagnetic coil and moved in the valve casing. In accordance with signals supplied to the electromagnetic coil, the amount of movement and the direction of movement are changed. Thus, the output portion to be opened is changed. Specifically, a refrigerant gas introduced into the valve casing through the inlet portion is discharged from the outlet portion determined by the position of the valve body, and thus the passage of flow is switched.
Although the flow passage can be quickly switched by means of the four-way valve, the four-way valve has the following shortcomings:
1) Since the piping for constituting the refrigeration cycle is complicated, a large space is needed for the piping, and the size of the air-conditioning apparatus itself cannot be reduced. PA1 2) Since the four-way valve has complex construction, an internal leak occurs, resulting in a decrease in performance, higher possibility of fault, and an increase in cost. PA1 3) Since power is constantly supplied to the electromagnetic coil for driving the valve body, the power consumption increases. PA1 a valve body to which a plurality of fluid passages are connected; PA1 a slider having a gas passage capable of selectively connecting two of said plurality of fluid passages connected to the valve body; PA1 a balance port formed in said slider to let said gas passage communicate with the outside of the slider; PA1 a pilot valve for opening and closing said balance port; PA1 a moving mechanism for moving said pilot valve and said slider as one body in a predetermined direction alone; and PA1 forwardly and reversely rotatable driving means for driving said pilot valve, along with said moving mechanism, to open said balance port, thereby canceling a pressure difference between the inside and outside of the slider, and then moving the slider to switch said fluid passages. PA1 a casing body to which a plurality of fluid passages are connected; PA1 a compressor mechanism unit contained in said casing body; PA1 a motor unit contained in said casing body and comprising a stator and a rotor; and PA1 a switching valve, contained in said casing body, for switching said fluid passages, PA1 said switching valve comprising: PA1 a casing body to which a plurality of fluid passages are connected; PA1 a motor unit including a compressor mechanism unit, a stator and a rotor all contained in said casing body; PA1 a switching valve, contained in said casing body and connected to said fluid passages, for selectively connecting two of said plurality of fluid passages; and PA1 magnetic coupling means, provided between said switching valve and said motor unit, for magnetically coupling the switching valve and the motor unit, thereby transmitting a driving force of the motor unit to the switching valve. PA1 a fluid compressor for compressing a fluid; PA1 a switching valve for switching fluid passages in said fluid compressor for flowing a non-compressed low-pressure fluid and a compressed high-pressure fluid; PA1 an indoor heat exchanger and an outdoor heat exchanger connected to said switching valve via pipes; and PA1 a restriction device provided between the indoor heat exchanger and the outdoor heat exchanger, PA1 said switching valve comprising:
In order to obviate these shortcomings, a system has been proposed, wherein a four-way valve is contained in the casing of the fluid compressor constituting a part of the refrigeration cycle and the four-way valve is switched by an electromagnetic drive actuator.
In the case of the fluid compressor, however, an actuator is contained in the casing body and power terminals are required. Consequently, the size of the compressor inevitably increases and the cost increases.
Furthermore, forcible gas balancing means for use in switching the four-way valve is not provided. Consequently, it is necessary to wait for the coming of a gas balance state after the system is stopped. Then, the force acting on the valve has decreased, the valve must be opened/closed.
Normally, it takes several minutes to wait for the coming of the gas balance state. For example, when the heating mode is switched to the defrosting mode, the time for defrosting increases. As a result, the heating performance decreases and the comfortability lowers.